Film forming method and film forming apparatus
09966256 ยท 2018-05-08
Assignee
Inventors
- Satoshi Takagi (Nirasaki, JP)
- Kazuya Takahashi (Nirasaki, JP)
- Hiroki Murakami (Nirasaki, JP)
- Daisuke Suzuki (Nirasaki, JP)
Cpc classification
C30B1/026
CHEMISTRY; METALLURGY
H01L21/02667
ELECTRICITY
H01L21/0262
ELECTRICITY
C23C16/22
CHEMISTRY; METALLURGY
International classification
C23C16/00
CHEMISTRY; METALLURGY
C23C16/52
CHEMISTRY; METALLURGY
C23C16/455
CHEMISTRY; METALLURGY
H01L21/02
ELECTRICITY
Abstract
There is provided a method of forming a film on a surface to be processed of a workpiece, the method including: accommodating the workpiece with a single-crystallized substance formed on the surface to be processed, into a processing chamber; supplying a crystallization suppressing process gas into the processing chamber such that a crystallization of the single-crystallized substance formed on the surface to be processed is suppressed; and supplying a source gas into the processing chamber to form an amorphous film on the surface to be processed of the workpiece.
Claims
1. A method of forming a film comprising: preparing a workpiece with a crystallized silicon film or a silicon-germanium film formed on a surface of the workpiece; accommodating the workpiece into a processing chamber; supplying a crystallization suppressing process gas into the processing chamber such that a crystallization of a film to be formed on the crystallized silicon film or the silicon-germanium film is suppressed such that a lattice constant is changed on an entire surface of the crystallized silicon film or the silicon-germanium film; and after supplying a crystallization suppressing process gas, supplying a source gas into the processing chamber to form an amorphous film on the crystallized silicon film or the silicon-germanium film, wherein the crystallization suppressing process gas is selected from a group consisting of a phosphine-based gas, a borane-based gas, a hydrocarbon-based gas, and an organosilane-based gas.
2. The method of claim 1, further comprising: removing an oxide film from a surface of the crystallized silicon film or the silicon-germanium film before supplying a crystallization suppressing process gas.
3. The method of claim 2, wherein a hydrogen-containing gas is used in removing the oxide film.
4. The method of claim 1, further comprising: crystallizing the amorphous film after supplying a source gas.
5. The method of claim 1, wherein the film to be formed on the crystallized silicon film or the silicon-germanium film includes one of a silicon film, a germanium film and a silicon-germanium film.
6. The method of claim 1, wherein the source gas includes one of silicon, germanium and silicon-germanium.
7. The method of claim 1, wherein the amorphous film includes one of an amorphous silicon film, an amorphous germanium film and an amorphous silicon-germanium film.
8. A method of forming a film on a surface of a crystallized silicon film or a silicon-germanium film, the method comprising: changing a lattice constant of the entire surface of the crystallized silicon film or the silicon-germanium film; and after changing a lattice constant, forming an amorphous film on the surface of the crystallized silicon film or the silicon-germanium film, wherein a phosphine-based gas, a borane-based gas, a hydrocarbon-based gas, or an organosilane-based gas is used in changing a lattice constant.
9. The method of claim 8, further comprising: removing an oxide film from the surface of the crystallized silicon film or the silicon-germanium film before changing a lattice constant.
10. The method of claim 8, further comprising: crystallizing the amorphous film.
11. The method of claim 8, wherein the amorphous film includes one of an amorphous silicon film, an amorphous germanium film and an amorphous silicon-germanium film.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
DETAILED DESCRIPTION
(10) Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Throughout the drawings, like reference numerals denote the same or similar elements or functionality. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.
First Embodiment
(11) <Film Forming Method>
(12) A first embodiment of the present disclosure mainly relates to a homo-epitaxial growth.
(13)
(14) First, as shown in
(15) Subsequently, as shown in step S1 of
(16) Subsequently, as shown in step S2 of
(17) The inventors of the present disclosure have found that, when a crystallized Si is grown on a single-crystallized substance (e.g., the single-crystallized Si substrate), facets are generated on a surface of the crystallized Si, which are caused by a very small amount of oxygen atoms remaining on the surface to be processed of the single-crystallized Si.
(18)
(19) A thin SiO.sub.2 film such as the native oxide film 2 can be removed by the wet cleaning or the COR process in step S1. However, for example, as shown in
(20) As a result, as shown in
(21) In order to suppress the generation of the pyramid-like facets 6, according to the first embodiment of the present disclosure, the thin SiO.sub.2 film such as the native oxide film 2 is removed by the wet cleaning or the COR process, and subsequently, the remaining oxygen atoms are removed.
(22)
(23) As shown in
(24) To address this, as shown in
(25) As described above, in the crystallization suppressing process of step S2 of
(26) An example of process conditions applied in Step S2 is as follows:
(27) Flow rate of PH.sub.3: 100 to 1,000 sccm
(28) Process time: 1 to 60 minutes
(29) Process temperature: 300 to 800 degrees C.
(30) Process pressure: 133.3 to 53320 Pa (1 to 400 Torr)
(31) (wherein 1 Torr is defined as 133.3 Pa)
(32) While in this embodiment, the PH.sub.3 gas, i.e., a phosphine-based gas (PH.sub.3, P.sub.2H.sub.4, etc.) is used as a gas for the crystallization suppressing process, other gas such as a borane-based gas, a hydrocarbon-based gas or an organosilane-based gas may be used as the crystallization suppressing process gas. That is to say, any gas containing phosphorus (P), boron (B) and carbon (C) or the like may be used as the crystallization suppressing process gas.
(33) Subsequently, as shown in step S3 of
(34) An example of process conditions applied in Step S3 is as follows:
(35) Flow rate of Si.sub.2H.sub.6: 10 to 1,000 sccm
(36) Process time: 1 minute or more
(37) Process temperature: 350 to 450 degrees C.
(38) Process pressure: 13.3 to 1333.3 Pa (0.1 Torr to 10 Torr)
(39) In this embodiment, the Si.sub.2H.sub.6 gas is used as the silicon source gas, but is not limited thereto. In some embodiments, a hydrogen-silicon-containing gas may be used as a source gas for forming the amorphous Si film 4.
(40) Subsequently, as shown in step S4 of
(41) An example of process conditions applied in Step S4 in the inert gas atmosphere is as follows:
(42) Process time: 60 minutes
(43) Process temperature: 300 to 1000 degrees C.
(44) Process pressure: 133.3 to 101,308 Pa (1 to 760 Torr)
(45) Although in this embodiment, the solid-phase epitaxial growth process has been described to be performed in the inert gas atmosphere, the present disclosure is not limited thereto. In some embodiments, the solid-phase epitaxial growth process may be performed in a hydrogen gas atmosphere or a state in which an interior of the processing chamber of the film forming apparatus is vacuumed.
(46) As described above, according to the silicon film forming method of the first embodiment of the present disclosure, the crystallization suppressing process is performed on the surface to be processed of the single-crystallized Si, and subsequently, the amorphous Si film 4 is formed on the surface to be processed of the single-crystallized Si. Thus, it is possible to suppress irregularities such as the facets from being generated on the surface to be processed when the amorphous Si film 4 is crystallized.
(47) Further, in the first embodiment, the crystallized Si is formed on the single-crystallized Si, but is not limited thereto. In some embodiments, a crystallized Ge may be formed on a single-crystallized Ge. In some embodiments, a crystallized SiGe may be formed on a single-crystallized SiGe.
Second Embodiment
(48) <Film Forming Method>
(49) A second embodiment of the present disclosure mainly relates to a hetero-epitaxial growth.
(50)
(51) As shown in
(52) First, as shown in steps S1 and S2 of
(53) Subsequently, as shown in step S3a of
(54) An example of process conditions applied in Step S3a is as follows:
(55) Flow rate of SiH.sub.4: more than 0 to 5,000 sccm
(56) Flow rate of GeH.sub.4: more than 0 to 5,000 sccm
(57) Process time: 5 minutes or more
(58) Process temperature: 250 to 450 degrees C.
(59) Process pressure: 13.33 to 533.2 Pa (0.1 to 4 Torr)
(60) While in the second embodiment, the SiH.sub.4 and GeH.sub.4 gases has been described to be used as the silicon-germanium source gas, the present disclosure is not limited thereto. In some embodiments, other gas may be used as the source gas for forming the amorphous SiGe film 8 as long as it contains hydrogen, silicon and germanium.
(61) The second embodiment relates to the so-called hetero-epitaxial growth in which a crystallized SiGe film is formed on a single-crystallized Si. This hetero-epitaxial growth causes misfit transitions due to a crystal mismatch. In the second embodiment, a lattice constant of Si of the wafer 1 is different from that of the crystallized SiGe film 8a. As such, the misfit transitions 7 occur in the crystallized SiGe film 8a, as shown in
(62)
(63) For example, as shown in
(64) In order to suppress the generation of the stepped portions caused by the misfit transitions 7, it is necessary to change the lattice constant of the surface to be processed of the wafer 1 before forming the amorphous SiGe film 8, like the first embodiment. In the second embodiment, the lattice constant of the surface to be processed of the wafer 1 has been changed in step S2 of
(65) Subsequently, as shown in step S4 of
(66) According to the silicon-germanium film forming method according to the second embodiment of the present disclosure, the crystallization suppressing process is performed on the surface to be processed of the single-crystallized Si, and subsequently, the amorphous SiGe film 8 is formed on the single-crystallized Si. The misfit transitions 7 occur in the crystallized SiGe film 8a obtained by crystallizing the amorphous SiGe film 8. In this state, the solid-phase epitaxial growth process is performed. Thus, the misfit transitions 7 are generated to be restricted inside the amorphous SiGe film 8, compared to the case where the crystallization suppressing process is not performed. Accordingly, it is possible to suppress irregularities such as the stepped portion caused by the misfit transitions 7 from being generated on the surface of the crystallized SiGe film 8a obtained by crystallizing the amorphous SiGe film 8.
(67) In addition, while in the second embodiment, the crystallized SiGe has been described to be formed on the single-crystallized Si, the present disclosure is not limited thereto. In some embodiments, a crystallized Ge may be formed on the single-crystallized Si. Further, in some embodiments, a crystallized SiGe or a crystallized Si may be formed on a single-crystallized Ge. Alternatively, a crystallized Si or a crystallized Ge may be formed on a single-crystallized SiGe.
Third Embodiment
(68) A third embodiment relates to a film forming apparatus which is capable of performing the film forming method according to the first and second embodiments of the present disclosure.
(69)
(70) As shown in
(71) The manifold 103 supports a lower end portion of the processing chamber 101. A wafer boat 105 of quartz, in which a plurality of (e.g., 50 to 120) semiconductor wafers (the silicon wafers 1 in this embodiment) is loaded as workpieces in multiple stages, is insertable into the processing chamber 101 through a lower portion of the manifold 103. The wafer boat 105 includes a plurality of supporting pillars 106, and the plurality of wafers 1 are supported by grooves (not shown) which are formed in each of the supporting pillars 106.
(72) The wafer boat 105 is loaded on a table 108 with a quartz heat insulating tube 107 interposed between the wafer boat 105 and the table 108. The table 108 is supported on a rotation shaft 110 that passes through a cover part 109. The cover part 109 is made of, e.g., a stainless steel, and opens or closes a lower end opening portion of the manifold 103. For example, a magnetic fluid seal 111 is disposed at a through portion of the rotation shaft 110. The magnetic fluid seal 111 closely seals and rotatably supports the rotation shaft 110. Also, for example, a seal member 112 such as an O-ring is disposed between a periphery of the cover part 109 and a lower end portion of the manifold 103, thus maintaining sealability in the processing chamber 101. The rotation shaft 110 is disposed at, e.g., a front end of an arm 113 that is supported by an ascending/descending instrument (not shown) such as a boat elevator. Accordingly, the wafer boat 105 and the cover part 109 are elevated in an integrated manner to be inserted into/separated from the processing chamber 101.
(73) The film forming apparatus 100 includes a process gas supply mechanism 114 configured to supply process gases into the processing chamber 101 and an inert gas supply mechanism 115 configured to supply an inert gas into the processing chamber 101.
(74) The process gas supply mechanism 114 includes a crystallization suppressing process gas supply source 117a, a Si-containing process gas supply source 117b, a Ge-containing process gas supply source 117c, and a crystallization process gas supply source 117d.
(75) In this embodiment, the crystallization suppressing process gas supply source 117a supplies a PH.sub.3 gas as the crystallization suppressing process gas into the processing chamber 101. The Si-containing process gas supply source 117b supplies a Si.sub.2H.sub.6 gas as the Si-containing process gas into the processing chamber 101. The Ge-containing process gas supply source 117c supplies a GeH.sub.4 gas as the Ge-containing process gas into the processing chamber 101. The crystallization process gas supply source 117d supplies a H.sub.2 gas as the crystallization process gas into the processing chamber 101.
(76) The inert gas supply mechanism 115 includes an inert gas supply source 120. The inert gas supply source 120 supplies an N.sub.2 gas as the inert gas into the processing chamber 101.
(77) In some embodiments, when the film forming apparatus 100 is tailored to form a silicon film, the Ge-containing process gas supply source 117c may be eliminated. Further, in some embodiments, when the film forming apparatus 100 is tailored to form a germanium film, the Si-containing process gas supply source 117b may be eliminated. Further, in some embodiments, when the film forming apparatus 100 is configured to supply the inert gas (e.g., the N.sub.2 gas) in the crystallization process, the crystallization process gas supply source 117d may be eliminated. In this case, the N.sub.2 gas as the crystallization process gas is supplied from the inert gas supply source 120 into the processing chamber 101.
(78) The crystallization suppressing process gas supply source 117a is coupled to a dispersion nozzle 123a through a flow rate controller 121a and an on-off valve 122a. Likewise, the Si-containing process gas supply source 117b is coupled to a dispersion nozzle 123b (not shown) through a flow rate controller 121b and an on-off valve 122b. Similarly, the Ge-containing process gas supply source 117c is coupled to a dispersion nozzle 123c (not shown) through a flow rate controller 121c and an on-off valve 122c. Similarly, the crystallization process gas supply source 117d is coupled to a dispersion nozzle 123d through a flow rate controller 121d and an on-off valve 122d.
(79) Each of the dispersion nozzles 123a to 123d, which pierces through the sidewall of the manifold 103 inward, bends upward, and extends vertically, includes a quartz tube. At vertical portions of the dispersion nozzles 123a to 123d, a plurality of gas discharge holes 124a to 124d is formed spaced apart from each other by a predetermined distance, respectively. The crystallization suppressing process gas, the Si-containing process gas, the Ge-containing process gas and the crystallization process gas are approximately uniformly discharged from the respective gas discharge holes 124a to 124d into the processing chamber 101 in a horizontal direction.
(80) The inert gas supply source 120 is coupled to a nozzle 128 through a flow rate controller 121e and an on-off valve 122e. The nozzle 128, which penetrates through the sidewall of the manifold 103, discharges the inert gas from a tip of the nozzle 128 into the processing chamber 101 in the horizontal direction.
(81) At a portion opposite to the dispersion nozzles 123a to 123d in the processing chamber 101, an exhaust vent 129 is installed to exhaust an interior of the processing chamber 101. The exhaust vent 129 has an elongated shape formed by chipping the sidewall of the processing chamber 101 in the vertical direction. At a portion corresponding to the exhaust vent 129 of the processing chamber 101, an exhaust vent cover member 130 with a C-shaped section is installed by welding to cover the exhaust vent 129. The exhaust vent cover member 130 extends upward along the sidewall of the processing chamber 101, and defines a gas outlet 131 at the top of the processing chamber 101. An exhaust mechanism 132 including a vacuum pump is connected to the gas outlet 131. The exhaust mechanism 132 exhausts the interior of the processing chamber 101 to discharge the process gas used for the process and to change an internal pressure of the processing chamber 101 into a process pressure adapted for the process.
(82) A cylindrical body-shaped heating device 133 is installed on an outer periphery of the processing chamber 101. The heating device 133 activates a gas supplied into the processing chamber 101, and heats a workpiece (e.g., the wafer 1 in this embodiment) loaded in the processing chamber 101.
(83) For example, respective parts of the film forming apparatus 100 are controlled by a controller 150 including a microprocessor (computer). The controller 150 is connected to a user interface 151. The user interface 151 includes an input part equipped with a touch panel or a keyboard for inputting, by an operator, a command to control the film forming apparatus 100, a display for visually displaying an operation state of the film forming apparatus 100, or the like.
(84) A memory part 152 is connected to the controller 150. The memory part 152 stores a control program for executing various processes in the film forming apparatus 100 under the control of the controller 150, and a program (i.e., a recipe) for executing respective processes in the respective components of the film forming apparatus 100 according to process conditions. The recipe is stored in, e.g., a memory medium of the memory part 152. The memory medium may include a hard disk, a semiconductor memory, or a portable memory such as a CD-ROM, a DVD, a flash memory or the like. The recipe may be suitably transmitted from other device through a dedicated line. If necessary, the recipe is read from the memory part 152 in response to a command received from the user interface 151, and the controller 150 executes a process according to the read recipe. Accordingly, the film forming apparatus 100 performs a desired process under the control of the controller 150.
(85) In this embodiment, the film forming methods according to the first and second embodiments are performed under the control of the controller 150. The film forming methods according to the first and second embodiments can be performed by the film forming apparatus 100 shown in
(86) Although the present disclosure has been described according to the first and second embodiments, the present disclosure is not limited thereto. A variety of modifications may be made without departing from the spirit of the disclosures.
(87) For example, while in the first and second embodiments, the crystallization suppressing process has been described to be performed on the surface to be processed of the wafer 1 (i.e., the single-crystallized Si which is originally formed as a single crystal), the same effects may be manifested even for a surface to be processed of a crystallized Si which is formed by crystallizing an amorphous Si using a solid-phase epitaxial growth process. That is to say, the first and second embodiments may be applied for either a workpiece made of an original single crystal or a workpiece crystallized (or single-crystallized) by a crystallization process.
(88) In the first and second embodiments, the crystallization suppressing process has been described to be performed on the surface to be processed of the single crystal Si or the crystallized Si such that the crystallized Si film 4a or the crystallized SiGe film 8a is formed. In some embodiments, the crystallization suppressing process may be performed on a surface to be processed of a single-crystallized SiGe or a crystallized SiGe such that the crystallized Si film 4a or the crystallized SiGe film 8a may be formed. Further, in some embodiments, a crystallized Si film, a crystallized Ge film or a crystallized SiGe film may be formed on the surface to be processed of a single-crystallized or crystallized Ge.
(89) Although specific process conditions are illustrated in the first and second embodiments, the process conditions are not limited thereto. In some embodiments, the process conditions may be varied according to a volume of a processing chamber in which a workpiece is accommodated, or a process pressure of the processing chamber, or the like.
(90) According to the present disclosure, it is possible to provide a film forming method and a film forming apparatus adapted to perform the film forming method, which are capable of suppressing irregularities from being generated on a surface of a crystallized Si film, a crystallized Ge film or a crystallized SiGe film due to a facet or a cross hatch pattern, even when the crystallized Si film, the crystallized Ge film or the crystallized SiGe film is respectively grown on a single-crystallized Si, a single-crystallized Ge or single-crystallized SiGe. In addition, according to the present disclosure, it is possible to provide a film forming method and a film forming apparatus adapted to perform the film forming method, which are capable of depositing an amorphous Si film, an amorphous Ge film or an amorphous SiGe film on a single-crystallized Si, a single-crystallized Ge or a single-crystallized SiGe, respectively.
(91) While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.